Rep. Tlaib offends fellow Democrats by telling the truth in public.

Democrats profess to be upset with Congresswomen Rashida Tlaib for daring to say in public about Donald J. Trump what they all think in private: “we’re gonna go in there and we’re gonna impeach the mother—.”

Apparently the Michigan freshman hasn’t been around long enough to know that Democrats are supposed to pretend that impeachment is a solemn legal matter rather than a political exercise. She also made the mistake of using foul language in a video that went viral, not that she’s apologizing for a word of it. But give...